Automatic knife block control assembly for a linecasting machine



United States Patent [72] Inventors Gerald A. Fasse and Eugene A.Mychalowych, Warren, Michigan [21] Appl. No. 717,304 [22] Filed March29, 1968 [45] Patented Oct. 27, 1970 [73] Assignee Booth Newspapers,Inc.

Detroit, Michigan a corporation of Michigan [54] AUTOMATIC KNIFE BLOCKCONTROL ASSEMBLY FOR A LINECASTING MACHINE 27 Claims, 8 Drawing Figs.

[52] U.S. Cl 199/59, 199/54 [51] Int. Cl B4lb ll/72 [50] Field ofSearchl99/59, 54. I8

[56] References Cited UNITED STATES PATENTS 3,291,294 12/1966 Netznik etal l99/59 3,300,034 1/1967 Kleboe et al l99/l 8X Primary Examiner-RobertE. Pulfrey Assistant Examiner-Eugene H. Eickholt AttorneyBarnard,McGlynn and Reising ABSTRACT: .A knife control assembly for use incombination with a linecasting machine of the type including a movableknife adjustable to various different slug-trimming positions. Thenormal linecasting machine includes a pair of coacting screw-typemembers one of which supports and moves the knife upon rotation of theother. The rotatable screw-type member is normally rotated manually,however, in accordance with the instant invention it includes a gear andis rotated by the control assembly of the instant invention. Theassembly of the instant invention includes a motor which rotates thisgear through a gear drive train upon receiving a signal from a controlmeans. There is included a multiposition circular switch having aplurality of contacts with each contact corresponding to each of certainselected trimming positions of the knife, and a magnetically closed reedswitch and a rotating magnet which closes the reed switch at each of theoperative positions of the circular switch. The control means sends asignal to the motor to move the knife to a selected trimming positionand when the circular switch reaches a position corresponding to theselected position, the magnet is in the p0sition to close the reedswitch thereby sending a signal to the control means to stop the motor,which in turn stops the knife at the precise selected position. Thecontrol means includes a register for storing a selected trimmingposition of the knife, a plurality of electronic gates coupled to theregister with the output of each gate being representative of a selectedtrimming knife position with the outputs of each of said gates beingcoupled to a contact of the circular switch.

Patented Oct. 27, 1970 Sheet IIOA.C.

INVENTORS Gent/a Afiirsse i Bm e e Azzgvchazo ch The instant inventionrelates to an improved automatic knife block control assembly for alinecasting machine. Although the invention will be described andillustrated in an Intertype linecasting machine it will be understood bythose skilled in the art that it is also applicable to other linecasting machines.

As is well known by those skilled in the art, an lntertype linecastingmachine includes a plurality of magazines which are selectively placedin an operative position for supplying matrices of particular fonts.Each font has a recess defining a mold for a particular alphanumericcharacter. When a particular magazine is in the operative position, thefonts are supplied to a casting position where the fonts are disposedone beside another and are placed in position adjacent a mold cavity sothat hot metal disposed in the mold cavity is impressed with the fontsto form a slug which in turn is used to define a line of print in acolumn of printed matter such as that in a newspaper. The mold disc hasseveral molding cavities and each cavity is useful for casting adifferent size of font. When a certain mold cavity is being utilized itis in the operative position and is rotated between a casting positionand an ejecting position where the slug (the piece of metal having theletters molded on one face thereof) is ejected through a knife blockwhere it is sized by severing or cutting the metal from its oppositesides.

In the Intertype linecasting machine, the knife block normally includesa stationary knife and a movable knife which is rectilinearly movabletoward and away from the stationary knife so that the distance betweenthe knives changes for sizing slugs having different distances betweenthe sides. The reason for the differences in distance between the sidesis because of the different sizes of letters molded on the slugs, i.e.,the different sizes of fonts utilized in the casting step. In

the basic lntertype machine the position of the movable knife isdetermined by an indexing assembly having dials and including a memberwhich is manually rotatable to a selected position to move the movableknife to the approximate desired position. One of the problems with thisassembly is, of course, the level of accuracy obtainable in manuallypositioning the movable knife. In other words, the tolerances to whichthe movable knife may be positioned by manually indexing such anassembly are indeed not very precise.

Recently there have been developments wherein the movement of themovable knife is automated. The problem with such mechanisms is one ofnot having the capability of moving the movable knife to a positionwithin the desired tolerances. In other words, such assemblies are notcapable of moving the knife to a position of the desired preciseness.The reason for this is exemplified in a prior art mechanism whichincludes a plurality of mechanical stop members which coact and engageone another to control the position of the movable knife member. Suchmechanical stops do not provide the desired preciseness in positioningthe movable knife.

Accordingly, it is an object and feature of this invention to provide animproved automatic knife block control assembly adapted to move themovable knife to a position which is within closer tolerances of thedesired position than heretofore unobtainable.

In correlation with the foregoing object and feature, it is an objectand feature of this invention to provide a knife control assemblyincluding actuation means for moving the knife between trimmingpositions with course sensing means for providing a signal when theknife approaches the selected trimming position anda fine sensing meansfor providing a signal when the knife reaches the selected trimmingposition to deactivate the actuation means whereby the knife stopsmoving at a position which is within closer tolerances to the desiredposition than heretofore obtainable.

In correlation with the foregoing objects and features, another objectand feature of this invention is to provide 'a switch with eachoperative position thereof corresponding to a selected trimming positionof the knife and wherein the fine sensing means includes a magneticallyclosed reed switch and a rotating magnet which closes the reed switch asthe circular switch reaches each position thereof.

In correlation with the foregoing objects and features, another objectand feature of this invention is to provide an actuating means whichincludes'a motor andcontrol means which reverses the motor as themovable knife reaches each extreme position of movementifor stopping themotor means only when the movable knife reaches the selected trimmingposition during movement of the knife from the extreme fully openedposition toward the fully closed positionythus, reducing backlash in themechanical drive means of the actuation means so that the knife may bepositioned within the tolerances desired.

Another object and feature of this invention is to provide means wherebythe knife can be-set automatically and also by manual switching means.

In correlation with the foregoing objects and features, a control meansis provided including a register adapted to be set by manual switchingmeans and also by signals received from a decoding means.

Other objects and attendant advantages of the present invention will bereadily appreciated as the same becomes better understood by referenceto the following detailed description when considered in connection withthe accompanying drawings wherein:

FIG. l-is a fragmentary plan view showing a preferred embodiment of aknife control assembly and a portion of a linecasting machine assembly;

FIG. 2 is a view taken substantially along line 2-2 of FIG. 1;

FIG. 3 is a fragmentary cross-sectional view of a portion of theassembly;

FIG. 4 is a cross-sectional view taken substantially along line 4-4 ofFIG. 1;

FIG. 5 is a cross-sectional view taken substantially along line 5-5 ofFIG. 4;

FIG. 6 is a schematic of the control means of the preferred embodimentof the invention;

FIG. 7 is a schematic of the motor control means of the preferredembodiment of the invention; and

FIG. 8 is a schematic of the extreme position-sensing means of theinvention.

Constructive details of the linecasting machines are well known to thoseskilled in the art and will not be set forth in detail herein except asnecessary. Reference may be had to a manual published by the IntertypeCorporation, copyright 1943, and entitled The Intertype for a specificdescription of an Intertype line casting machine with which the instantinvention may be utilized. Reference may also be had to the officialmanual of the Mergenthaler Linotype Company, Brooklyn, N.Y., copyright1940, and entitled Linotype Machine Principles for an understanding andmore specific description of a Linotype machine of the type with whichthe instant invention may be utilized.

Referring now to the drawings wherein like numerals indicate like orcorresponding parts throughout the several views, a knife controlassembly is shown in combination with a portion of an Intertypelinecasting machine generally at 10.

' The linecasting machine includes a stationary knife 12 and a movableknife 14. The movable knife 14 is movable rectilinearly toward and awayfrom the stationary knife 12 between a fully .open position and a fullyclosed position. The space betweenthe knives l2 and 14 determines thethickness of the distance between the sides of the slugs being trimmed.The circular member 16 is a stationary part of the linecasting machineand is a screw member which coacts with another screw member 18. Thescrew member 18 supports the movable knife 14 and moves the knife 14toward and away from the stationary knife 12. In other words, the screwmembers 16 and 18 coact together through the screw threads 20 androtation A: .t... M..." mnmhnr IR causes it in move axiallv therebymachine.

knife is approaching the selected trimming controlassembly also includesa fine sensing means, whichis generallyindicatedat 30 in FIG. 3, forproviding a signal when appreciated thatnas the arm movesjinto The knifecontrol assembly includes a support plate 22 which is clamped aboutthescrew member 16 and firmly held thereto by a bolt '24. Other brackets(not shown) may also be 6 utilized to secure. the support plate 22 onthe linecasting The knife controlassembly includesactuation meansgenerally shown at 26,for moving the. knife 14 between.

trimmingpositionsi The knife control assembly also includes coursesensing means generally indicated at 28"fo r providing a signalwhen theknife is nearerto the selected trimming .position than any othertrimming position-That is to say,'the

kriife .14 may bemoved to any one of various different selected trimmingpositions all-of whichare at a different 7 distancefrom the stationaryknife 12.. When the knife14 is very close to the desired ,orselectedtrimming position, the

course sensing means position. The knife provides a signalindicatingthat the the knife'14reaches the selected trimming positionto'deactivate the actuation means 26 whereby the knife stops moving..

The course sensing, means predetermined spaced positions whichcorrespond generally to the respective trimming positions of the knife14 so that the course sensing means 28 provides a signal when the knife14 is very nearly in theselected trimming position. More specifically,the course sensing means 28 is a multiposition circular switchwith eachoperative position of the switch correspondingto a trimming position.The switch maybeone having a plurality of contacts disposed in a circlewith a rotary arm moving from one contactto the other and with eachcontact corresponding toa trimming position of the knife. It will beengagement with ,a

given contact to establish electrical current flow, the knife 14 is notquite at the precise desired selected trimming position.

The fine sensing means 30 includes a magnetically closed reed switch 32and a rotating magnet 34 which closes the reed switch 32 at eachposition of the circular switch of the course sensing means28. In otherwords, the gearing, as will be explained morefully hereinafter, issuch'that the magnet 34 is moved intoposition for closing the reedswitch 32 each time 28 includes a plurality: of;

The course sensing means 28 also includesa first drive means forrotating the circular switch in response to rotation of therotatingscrew member 18. This first drive means includes the shaft 54, which isrotated by the spur gears 56 and 58, the latter gear being in drivingengagement with the gear 50 because of a pin 60..

The fine sensing means includes a second drive means for rotating themagnet 34 in response torotation of the rotating screw member 18-(i.e.,in 'responseto movement of the knife 14). The seconddrive means includesthe gears 62, 64,

'66 and 68. A shaft'70 is rotatablysupported in the bearings 72. Thegear 52 is nonrotatablylsecured thereto byfthe pin 74, a

the gears 50 and 58, as previously mentioned being secured thereto bytheipin 60,- and the gear:68 being securedtheretp 5 I V I v i in by thepin 76. 1

The component 7 v tually a double-deck switch. Onedeck defines thecircular switch and the other deck is a component of the control meansand has two positions, one position to indicate when the knife l4isfully closed and one'position to indicate when the knife 78 is shownsche-- 14 is fully open. This deck of component matically with referenceto FlG. 8. Hence, a signal is provided for reversing the direction ofrotation'of themotor means 36 when the knife reaches the extremepositions of movement. The component 78 includes alook-through, clearface 80 behind-which is disposed a disc 82.with indices thereon. Theindices, as best illustrated in FIG. 2, are marked off from 4 to 36.

The indices 4 to 36 indicate the number of points.A point is a measureof thickness of the slug which,in turn, is a function of the height ofthe letters on a printed page. Each point equals fourteen-thousandths(0.014) of an inch. In the devicesillustrated, the. knife maybepositioned at any selected trimming position which is at an equalnumberof points between and including 4 and 36 points, i.e., 4, 6, 8,10, etc. When a signal is provided to position the knife 14 at aselected trimming posimotor means 36 rotates to rotate the in turn movesthe knife 14'. If the knifef14is initially at the 10- signal which.stops the actuating means 26,.thereby stopping the knife 14 in theprecise desired position, unless the circular switch; is in the(position corresponding to. the selected trimming position. l

- The actuation means closed positions, and inthe slo-syn motorwhich isshown schematically in F IG. 7. There is the motor means only when themovable knife 14 reaches the selected trimming position during movementthereof from the fullyfopen position towardthe fully closed position. Inother.

words, the desired selected trimming position of the knife l4 is onlyreached asathe movable knife 14 is moving toward the stationary knife12..Ihe means to accomplish this will become The'screw member 18 has afirst gear 40 secured thereto by the bolts 42. The actuation means alsoincludes a gear train for transmitting motionbetween the motor means 36and the first gear 40. That geartrain includes the bevel gears 44 and46, thespur gears, 48, and 52, the latter gear being in meshingengagement with the first gear 40. i

7 26V includes a reversible motormeans 36 for moving the movableknife 14between the'openand preferred embodiment is a 72 pole also includedacontrol meansas shown in FIGS. 6 through 8 to reverse the motor means 36when the knife 14 reaches each, of the fully open and fully closedpositions andfor stopping point position and the signal is to positionthe knife 14 at the 20-point position, the motor rotates in thedirection to move the knife 14 toward the stationaryknife 12.When theknife 14 reaches the fully closed position the other switch is activatedto provide a signal which is utilized to reverse thedirection orrotation of the motor 36 so that the k nife 14 moves away from .thestationary" knife 12. The knife then moves away from the stationaryknife 12 until it reachesthe fully open position, i.e., it does not stopat the desired position of 10 points. When the knife 14 reaches thefully open position, the switch forming a second deck of thecomponent'78provides another signal which again reverses the, directionof rotation of the motor means 36 to move the knife toward thestationary knife'12 until the arm in the'circularswitch engages thecontact corresponding to the 10-point position. Currentis then sentthrough the circular switch. However, the circular switch is in serieswith the reed switch 32. The drive gears 62, 64, 66 and'68 however movethe magnet 34 into'position relative to the reed switch 32 so as toclose .the reed switch 32 when the knife 14 is at or withinthe desiredtolerances of the selected trimming position. By utilizing the course,and fine sensing means respectively, the knife 14 maybe moved to withinonethousandth (0.001) of an inch of the exact precise position. In

other words, the knife control assembly 'of the instant invention maymove a knife within one-thousandth (0.001) of an. inchintolerance.Furthermore, as alluded to above, the

system only reaches the selected trimming position whenthe knife 14isfmoving toward thestationary knife 12, thus eliminating backlash inthe mechanical drive systems and further allowing. the knife to bepositioned within onethousandth (0.001 of an inch in tolerance.

"There is also. included a manually actuatable drive means comprisingthe knurled wheel 84 for rotating the gears 48, 50,

52 and 40 tornove the knife 14. Theindicator face ordial 82,

therefore, provides an indicator means for indicating the positionof theknife an'd is particularly useful when the position thereof'is manuallyadjusted by rotating the wheel 84.

78 includes the circular switch butts ac Now to more specificallydescribe the control means 38,

---" and with particular reference to FIGS. 6 through 8 it should firstbe noted that the control means 38 is designed to operate in conjunctionwith the auxiliary function control means disclosed in copending US.Pat. application Ser. No. 717,328, filed Mar. 29, 1968 entitledAutomaticSaw Control Assembly for a Linecasting Machine" tiled simultaneouslywith this application and which is assigned to the assignee of thisapplication. However, it should be understood that any means forelectronically or otherwise developing a signal representative of thevarious positions of movable knife 14 may be employed with the inventionherein disclosed.

The system of the aforesaid U.S. Pat. application Ser. No. 717,328utilizes a means for applying numbers in the standard teletype codealong with coded letters representing auxiliary linecasting machinefunctions such as the knife block (K), the saw (S), and mold disc (D) tothe decoder. The output of the decoder represents digits in the 8-42lBCD code and also has outputs for each auxiliary function such as K, Sand D and their inverses. Such outputs are used by control means 38 ashereinafter described.

Turning now to FIGS. 6 through 8, there is schematically shown controlmeans 38 for controlling either automatically or semiautomatically theposition of knife 14 in response to the movement of gear 40. The newselected or command position for the knife is placed in a commandposition register 100 either from the decoder of the aforesaidapplication or semiautomatically by manual switching means (not shown).Register 100 consists of four flip-flops 102, 104, 106 and 108. Eachflip-flop is preferably formed from a pair of NAND gates arranged in thewell-known manner and has set and reset input lines, and 0 and 1 outputlines in the well-known conventional manner. The register 100 isdesigned to store a decimal digit in the 8-4-2-1 BCD code with flip-flop102 storing the ones digit, flip-flop 104 storing the twos digit,flip-flop 106 storing the fours digit, and flip-flop 108 storing theeights digit. The set line for flip-flop 102 is connected by means ofline 110 to a semiautomatic switching means, generally an electronicdecade switching means (not shown), and lines 112, 114 and 116 aresimilarly connected with respect to flip-flops 104, 106 and 108respectively. Lines 110, 112, 114 and 116 enable the register 100 to beset semiautomatically by an operator operating the switching means. Theset line of flip-flops 102, 104, 106 and 108 are also connected to theoutputs of NAND gates 118, 120, 122 and 124 respectively. One input lineof gates 118, 120, 122 and 124 respectively are the 1,2, 4 and 8 linesrespectively from the decoder of the aforesaid application. The commoninput to gates 118, 120, 122 and 124 is the 1 output from controlflip-flop 126. Flip-flop 126 has its set line connected to the K linefrom the decoder of the aforesaid application and consequently isgenerally maintained in the reset state, being set by a signal appearingon the K line. The reset line of flip-flop 126 is connected throughinverter 128 to NAND gate 130 whose inputs are the inverses of the otherauxiliary function lines. As is apparent, only when flip-flop 126 is inthe set state will gates 118, 120, 122 and 124 let information carriedon lines l, 2, 4 and 8 pass to register 100.

The output from flip-flops 102, 104, 106 and 108 are connected to ameans for converting numbers in the 8-4-2-1 BCD code to decimal digitsand is formed by coupling NAND gates 132, 134, 136, 138, 140, 142, 144,146 and 148 to the outputs of flip-flops 102, 104, 106 and 108. Gate 132has its inputs connected to the 1 output of flip-flop 102 and the 0outputs of flip-flops 104, 106 and 108. Gate 134 has as its inputs the 0outputs of flip-flops 102, 106 and 108 and the 1 output of flip-flop104. Gate 136 has as its inputs the 1 output of flip-flops 102 and 104and the 0 output of flip-flops 106 and 108. Gate 138 has as its inputsthe 0 outputs of flip-flops 102, 104 and 108 and the 1 output of 106.Gate 140 has as its inputs the 1 output of flip-flops 102 and 106 andthe 0 output of 104 and 108. Gate 142 has as its inputs the 1 output offlip-flops 104 and 106 and the 0 output of 102 and 108. Gate 106' andthe 0 output of 108. Gate 146 has as its inputs the 1 output offlip-flop 108 and the 0 output of 102, 104 and 106. Gate 148 has as itsinputs the 1 output of flip-flops 102 and 108 and the 0 outputs of 104and 106. As is readily apparent, the outputs of gates 132, 134, 136,138, 140, 142, 144, 146 and 148 represent 9 knife positions, 1, 2, 3, 4,5, 6, 7, Sand 9 respectively. When one of the latter positions is storedin BCD form in register 100, the output of its corresponding NAND gateis at ground, with all other NAND gate outputs being positive.

In order to activate the system in response to information being placedin register 100, NAND gate 150 is utilized having as inputs the 0outputs of each of flip-flops 102, 104, 106 and 108. The output of gate150 is applied to the base of NPN transistor 152 whose emitter isgrounded and whose collector is coupled to a 24-volt source through theenergizing circuit of normally open relay 152. The base oftransistor 154is also coupled to a S-volt source so that in the absence of any numberbeing stored in register the output of gate is grounded biasingtransistor 152 off so that relay 154 hereinafter described is open.However, when a number is stored in register 100, transistor 152 isturned on and relay 154 is thus closed.

A 24-volt source is connected through relay 154 and relay energizingcircuit 156 to ground. When relay 156, as shall hereinafter be describedwith reference to HO. 7 is closed, motor means 36 is turned on. Withparticular reference to FIG. 7, slo-syn motor means 36 is shownschematically having a pair of windings 158 and 160 with one terminal ofeach of windings 158 and 160 being coupled together through resistor 174and capacitor 176. Winding 158 is connected from one terminal of all0-volt-AC source, triac 168, and normally open relay'156 to the othersource terminal. The gate of triac 168 is coupled through normally openlatching relay 162, resistor and winding 158 to a terminal of the ACsource. Winding 160 is connected from one terminal of a l l0-volt-ACsource, triac 166 and normally open relay 156 to a terminal of all0-volt-AC source. The gate of triac 166 is coupled through normallyclosed latching relay 162, resistor 172 and winding 160 to a terminal ofthe source. As is apparent, when relay 156 is closed, either triac 166or 168 conducts depending on the state of the energizing circuit ofrelay 162 to be hereinafter described. Thus, the motor 36 is driven inone of two directions when relay 156 is closed depending on relay 162.

Now with reference to the extreme position sensing means of FIG. 8,relay 162 is controlled by a second arm 164 of the component 78. Thisarm is designed to indicate when the knife is in either of the twoextreme positions. When the arm as shown by the broken line of FIG. 8indicates that knife 14 is in the fully closed position, a 24-voltpotential is applied across the latching coil 162L of relay 162 wherebythe normally closed relay contacts 162 are latched open and the normallyopen contacts are latched closed. In contrast, when arm 164 as shown inFIG. 8 indicates that the knife 14 is in the fully open position, itapplies a 24-volt potential across the unlatching coil 162U of relay 162whereby the normally closed relay contacts 162 previously opened by coil[62L are closed and the normally open latch relay contacts 162previously closed by coil 162L are opened. Thus, the latching andunlatching coils 162L and. 162U as shown in FIG. 8 control which oftriacs 166 and 168 are open and hence which one of windings 158 and 168is energized.

In order to stop motor 36 when knife 14 has reached the indicatedposition, the arm of component 78 shown schematically as 166 of FIG. 6as it sweeps the outputs of gates 132, 134, 136, 138, 140, 142, 144, 146and 148 is connected in series with reed switch 32, normally closedrelay 162 and reset line 178, the latter being coupled to the resetinputs of flip-flops 102, 104, 106, 108 and 126. When arm 166 sensesthat the output of one of the NAND gates 132, 134, 136, 138, 140, 142,144, 146 and 148 is at ground and also when the -4 11 in nlnnnr and inarlrlifinn \ul'mn nnrmallv closed relay 162 is latched closed, thenflip-flops of register 100 be reset opening relay 'l54-thus turning offthe system; Since relay 162 will be open only when the knife is movingtoward its.closed position, as hasbeen previously explained, backlash"is generally eliminated since the system will be shut otf only when aground potential issensed by arm 166 as knife l4. moves toward its fullyclosed position.

Placing line 178 at groundwill, as has'been mentioned, reset flip-flop126 if flip-flop l26. has notbeen reset by the receipt of anotherauxiliary function signal'at gate 130; Once, however, register 100 isreset the system .is stableandis able'to receive a newknifeicornmandpositioneither by signals from theencoder or'by signalsapplied bymanual switchingmeans sembly comprising; actuation means .for*moving the knife between the'trim'ming positions, coursesensing meansfor providing a signal when :the knife is nearer to a selected trimmingposition thanany other trimming position and fine sensing meansactivated by said signal for providing a stop signal when the knifereaches the selected trimming position to deactivate saidactuation meanswhereby the knife stops moving. 7 V

2. An assembly asset forth in claim 1 whereinsaid course sensing meansincludes a plurality of predetermined spaced positions; which correspondgenernlly 'to the :respeetive trimming positions of Jthe knife so thatsaid course sensing and only then .will the tions and for stopping saidmotor means only when said movaclosed'position. v n g w h13..An.assembly asset forth in claim 12 including a pair of.coacting.screwmembers one of which supports and moves 17. An assemblyas setforth in 12. An assembly as set forth in claim 11 wherein saidmotor means is reversible, and including control means torreversesaid-motor, means when said movable knife reaches said posibleknifereaches the selected trimming position during movement-threoffromsaid fully open position towardsaid fully said movable knife uponrotation of the other, the latter. in cluding a first gear,.and whereinsaid actuation means includes a gear train fortransmitting motionbetween said motor means and said first gear, a

14. An assembly as set forth inclaim 13 wherein said course sensingmeans is a multipositionl circular switch with each operative positionthereof .corresponding to a selected I trimming position.

15. An assembly as set forthin claim 14 wherein said coursesensingmeansincludesfirst drive meansfor rotating said cir- -a rotating:magnet which closes said reed switch upon each revolution thereof.

claim 16 wherein said fine sensing means includes second drive means forrotating said ineansprovides said signal therefrom when theknife is verynearly in theselected trimming position. 7

3..An assembly as set forth in claim 2 wherein said' course sensingmeans'is a multiposition circular switcnwith each 1 operative positioncorrespondingto a selected trimming position.

'4. An assembly as set forth in claim 3 wherein'saidfine sensing meansincludesa magnetically closed reedswitch and.

a rotating magnet whichclosessaid reedswitchat each position ,of saidcircular'switch.

5. An assembly as set forth in claim 2 wherein said actuation themovable knife reaches-the selected trimmingposition'dur- 1 ing movementthereof from-said fully open position toward said fully closed position.

means includes'motorrneans adapted for moving theimovable 7. An assemblyasset forth in claim 6 whcrein said course sensing means is amultiposition circular switchswith each operative position thereofcorresponding to a: selected. trimming position.

8. An assembly as set forth in claim7 wherein'said course sensing meansincludesfirst drive means adapted for rotating said circular switchinrespon'se to movement ofthe knife.

9. Anassembly as setforth inelaim 8 wherein said fine sensing meansincludes a magnetically closed reedswitch and a a rotating magnet whichcloses said reed switch uponeach revolution thereof. i 7

l0. Anasscmbly as set forth in claim'9 whereinsaid fine sensing meansincludes second drive means adapted for rotat-; ing said magnet inresponse to movement of the knife so that said magnet is in positionmtoclose said reed switchat each positionof said circular switch. 1

11. An assembly as set forth in claim; including a stationa .ry knife,.said movable knife being. rectilinearly movable toward and away fromsaid stationaryknife between a fully open position and a fully closedposition, and wherein saidacmagnet inresponse' to rotation of saidrotating screw member mthut saldmugnetis imposition to close said readswitch at each position of saldclrcular switch.

18. An assembly as set forth in claim 17 including manually actuatable';drive means formoving the' knife, and indicator "meansforindieating theposition of the knife.

19. A linecastingmachine assembly including a movable knife'adjustableto 'differentslug-trimming positions and a knife controlassembly comprising actuation means for moving said knife between saidtrimming positions, a register adapted for storing aselectedtrimmingposition of said knife, .aplurality of electronicgatescoupled-to said register, the output of each.ofsaid gatesbeingrepresentative of a selected trimming knife position, meanscooperatingwith saidoutputs of said gates for providing a'signal whensaid knife is nearer to a selected trimmingpositionthananyotheritrimming position,-

and fine sensing means activated by said signal for providing a stopsignal when said knife reaches the selected trimming position to.deactivatesaid actuation means whereby said knife stops moving.

20. An assembly as set forthin claim 19 wherein said re-.

contactswhen saidactuation means is-actuated.

tuationmeans includes motor means for moving said movable 22. Anassembly] as set forth in claimll wherein said actuation means includesmotor'meansand additionally including extreme positionmeans-forelectrically indicating a fully open signal and a fullycloscdsignal when said knife reaches its fully open and fully closed positionsrespectively and further wherein .said actuation means :includes,reversible motor .means, said motor 'means reversing upon receipt of.said fully openror'fully closedsignal means for maintaining said fullymeans is'deactivatedupon thesimultaneous receipt of said signalindicating that said .knife is nearer to a selected trimming positionthanany other trimming ,position,-said stop eianal fmm sairlfinnnensinumeans indicatin that saidknife signal for reversing thedirection of saidmotor means.

26. An assembly as set forth in claim 25 wherein said fine sensing meansincludes a magnetically closed reed switch and a rotating magnet whichcloses said reed switch at each contact of said multiposition switch.

27. An assembly as set forth in claim 26 wherein said arm iselectrically coupled to reset said register through said reed switchonly upon receipt of said fully open signal.

